Customize Description Line Field In Payables

In Oracle Fusion Payables - Manage Invoices, We have a requirement to concatenate the line description with the Business Unit Name automatically, but only if the 2nd segment in the Distribution Combination is equal to "****" .
I tried to do this using Application Composer, but I'm not able to see the Payables Business Objects.
Is there any other way to do this ?

Thanks in advance for your help.

KHI

#Payables